1. Field of the Invention
The invention relates to a test terminal block formed of a modular terminal block and a test plug block which can be clipped onto the modular terminal block, the modular terminal block having a plurality of modular terminals which are located next to one another and on both sides of the plurality of modular terminals one fastening clamp at a time, the test plug block having a plurality of tests plugs which are connected to one another and on both sides of the plurality of test plugs one fastening part at a time, the two fastening parts being connected to one another via a handle, each modular terminal having two busbars which together form an isolating point and each test plug having a contact plug which can be plugged into a isolating point, and the two fastening clamps each having a clamp housing with a guide groove and the two fastening parts each having a housing with a corresponding guide section which can be plugged into a guide groove. In addition, the invention relates to a module composed of a fastening clamp and a fastening part which can be connected to a test plug block for use in a test terminal block.
2. Description of Related Art
Electrical modular terminals have been known for decades and are being used in the millions in the wiring of electrical systems and devices. The terminals are generally locked onto mounting rails which for their part are often located in a plurality in a switching cabinet. Mainly screw terminals or tension spring terminals are used as conductor connecting elements. The clamping principle in tension spring terminals is similar to that of screw technology. While in the screw terminal, a tension sleeve draws the conductor against the busbar by the actuation of the terminal screw, in the tension spring terminal this task is assumed by the tension spring. But in addition insulation piercing connecting devices or torsion spring terminals can also be used.
In switching, measuring and control technology feed-through terminals with a disconnect possibility are the standard. The disconnect possibility which is implemented in the electrical modular terminal, i.e., the isolating point which is provided in the busbar, makes it possible here to plug different plugs with different functions into the terminal housing of the modular terminal, which plugs then make contact with the busbar at the isolating point. In addition to simple isolating plugs or through connectors, in particular, test plugs can also be used as plugs and can have special components, and they enable checking of the proper operation of the circuit which is connected to the modular terminal.
Electrical modular terminals which are generally made wafer-shaped, are often mated to several other electrical modular terminals to form a modular terminal block and are locked onto a mounting rail or mounted in a wall cutout, for example, of a switching cabinet. Accordingly, the individual test plugs, which correspond in their width generally to the width of the modular terminals, are joined into a test plug block and are seated jointly on a corresponding modular terminal block. In this case, there is the requirement that the number of interconnected modular terminals and the number of test plugs which are combined with one another into a test plug block can be freely selected. But at the same time the test plugs which have been combined into a test plug block should be able to be jointly actuated as simply as possible, i.e., should be able to be clipped jointly on the modular terminal block.
German Application 10 2005 025 108 B3 discloses a device for testing of a protective, measuring or counting apparatus, for example, of a protective line relay which has a pole strip which can be connected to the electrical apparatus with several successively arranged pole openings and a plug block with a number of pole tongues which corresponds to the number of pole openings. An individual pole strip module of the pole strip consists of a housing in which there are two contact tubes for connection of lines and spring-loaded contact clips which are connected to the contact tubes. The two contact clips can make contact by the pole tongue of a plug, the pole tongue of the plug having two pole segments which are separated from one another by a barrier. The barrier together with the corresponding pole opening in the pole strip module forms polarization which ensures that only one plug with a certain pole tongue can be inserted into a certain pole opening of a pole strip.
In the unplugged state of the plug or pole tongue into the pole strip, the two contact clips make contact with one another so that the two contact tubes are connected to one another in an electrically conductive manner and current can flow via a connected pole strip. If the plug with its pole tongue is pushed completely into the pole opening, the two contact clips are electrically separated from one another and the current flow is routed via the plug so that a test process can be carried out.
German Patent Application DE 10 2006 052 894 A1 and corresponding U.S. Pat. No. 7,666,037 B2 disclose a modular terminal, a test plug and a test plug block which consists of a plurality of modular terminals which are located next to one another and a corresponding number of test plugs, the individual modular terminals and the individual test plugs being similar in basic principle to the pole strip modules and pole plugs which are known from German Patent Application DE 10 2005 025 108 B3.
By using two fastening clamps and two fastening parts which are each located on the two sides of the modular terminal block or of the test plug block, the number of modular terminals and the number of test plugs which can be combined into a modular terminal block and a test plug block can be freely selected. The two fastening parts are connected to one another via a handle so that the test plug block together with the two fastening parts can be easily and comfortably plugged or clipped into the modular terminal block and the two fastening clamps using the handle. The handle is located on the top end of the fastening parts which have a larger cavity than the test plugs so that the handle spans the test plugs which are located between the two fastening parts and in this way can be comfortably grasped with one hand.
In order to ensure defined contact states when the test plug is plugged into the test opening, in the electrical modular terminal which is known from DE 10 2006 052 894 A1 and corresponding U.S. Pat. No. 7,666,037 B2, the busbars are made such that they form two contact regions which are located in succession in the direction in which the test plug is clipped on. In the known modular terminals thus the isolating point which is formed by the one end regions of the busbars is made in two stages. By forming a defined second contact region which is located in the insertion direction of the contact plug upstream of the first contact region, it is ensured that when the contact plug is inserted first a reliable electrical connection occurs between the contact plug and the two busbars before the first contact region is opened as the contact plug continues to be inserted, as a result of which the two busbars are then electrically separated from one another.
It is common to the above described known modular terminals and test plug blocks that the two busbars make contact with one another so that the conductor connecting elements are connected to one another in an electrically conductive manner when a plug has not been inserted into the modular terminal. If conversely a plug has been (completely) plugged into the modular terminal, the contact region is disconnected so that the conductor connecting elements are also electrically separated from one another.
Often, the individual test plugs of the test plug block have contact plugs of different length. When the test plug block is clipped on, then first the longer contact plugs of individual test plugs are immersed into the corresponding openings in the terminal housing of the modular terminals and make contact there with the leading contact region of the two busbars which is the first in the clip-on direction of the test plug. If the test plug block continues to be plugged onto the modular terminal block, the longer contact plugs are immersed into the second contact region, as a result of which this contact region is opened so that the electrically conductive connection between the two busbars—and thus also between the two conductor connecting elements which are connected to the busbars—is interrupted. If the contact plugs are electrically conductive, in this way, current conduction is bypassed via the test plug. When the test plug block continues to be plugged onto the modular terminal block, next the shorter contact plugs make contact first accordingly with the leading contact region in the modular terminals before the shorter contact plugs also open the second contact region, and in this way, also the current conduction of these modular terminals is interrupted and if necessary bypassed via the test plugs.
When the test plug block is pulled out of the modular terminal block, in many applications, it is necessary or at least desirable that the longer contact plugs still disconnect the contact region of the assigned modular terminals, while the shorter contact plugs are already pulled out of the second contact region of the assigned modular terminals so that the two busbars of the corresponding modular terminal again make contact, as a result of which current conduction via the modular terminal takes place. But here, in the known test terminal blocks, there is the risk that by pulling the test plug block out of the modular terminal block too quickly or too unevenly, the above described sequence is not reliably or properly ensured, after which the contact regions of some modular terminals are still opened by the longer contact plugs, while via other modular terminals to which test plugs with shorter contact plugs are assigned a current transition is already taking place. In this way, an unstable or undefined electronic state of individual modular terminals of the modular terminal block can arise.